The following invention relates in general to portable jib cranes, and more particularly to those jib cranes having a rotating mast between opposing pivot points.
There are many examples of jib cranes widely seen in the art to which the present invention pertains. These jib cranes vary in size from industrial uses to lightweight portable models used to lift motors from automobiles. While the current array of jib cranes are well suited for their intended purpose, there are many instances where they fall short in their ability to meet the needs of the user. In the most common practice, a jib crane has a mast and a boom. The boom is fitted with a lifting apparatus which allows one to attach lifting tackle to a heavy object, lift the object and allow re-location of the object.
As the present invention pertains to portable cranes, the type commonly associated with service repair trucks, the pertaining problems increase. Service repair trucks, usually fitted to a 1 ton chassis, comprise most of the equipment needed to repair on location. In many situations, the need to lift heavy parts into or out of the service truck is a common occurrence. As these service vehicles have open cargo beds, the cranes for the most part are able to meet these general lifting needs.
Another form of the service repair truck comprises a van body situated onto a heavy duty chassis. The advantages of the van, having an enclosed payload area, allow for protection from the elements, as well as security from theft. Most of these vans are of the same class as leisure/recreational vehicles therefore allowing for travel and parking anywhere, a convenience not available to other aforementioned service trucks. One advantage the open bed service trucks have on the van body type is the ability to lift and load objects to and from the bed without interferrence from side walls found with vans. The availability of lifting equipment is much greater for open bed trucks, wherein no such equipment is designated for use with vans, that is until the present invention.
In light of the numerous jib cranes widely seen in the art, no real consideration has been given in designating a crane for use with a van until the present invention. A typical practice whereby a jib crane would be used with a van would encompass one opening the rear swing-out doors of the van, rotating a boom/mast out of the van, sliding a lifting trolley over an intended payload and lifting the payload into the van by reversing the above steps. There are some jib cranes that claim this practice while being mountable within a van. These cranes all have a single axis point at the planar floor level and without a counter means to off-set the weight of a heavy object, would fail upon repetitive use. Those cranes which could bear the load are to heavy and cumbersome for use with the common van service vehicle.
Therefore having described the shortcomings of jib cranes with respect to usage with a van truck, a main object of the present invention is to provide a jib crane having a slidable lifting trolley along the jib member while being rotatably fixed between opposing axle points.
Another object of the present invention is to provide a a rotational jib crane, having a transversing trolley adapted for use with a lifting apparatus, for use with larger service trucks having an enclosed van body.
While it is yet a further object of the present invention to provide a rotating jib crane adapted for close placement to the perimeter of the cargo opening thereby preventing obstruction from objects entering or leaving the cargo area.